Automatic feedback mechanism for a medicament delivery device

Abstract

The present disclosure provides a feedback mechanism for a medicament delivery device, the feedback mechanism includes (i) a housing structure including a holding arm, (ii) a plunger rod configured to engage with the holding arm in a pre-tensioned state, and (iii) a signal generating member attached to the housing structure, the signal generating member including a resilient tongue which in the pre-tensioned state of the plunger rod is arranged in contact with a first portion of the plunger rod. The plunger rod includes a second portion arranged distally from the first portion, the second portion including a cut-out. The resilient tongue is operably arranged to, upon movement of the plunger rod in the proximal direction, be brought into contact with the second portion of the plunger rod to interact with the cut-out for generating an audible and/or tactile feedback.

1 - 14 . (canceled) 
     
     
         15 . A feedback mechanism for a medicament delivery device, the feedback mechanism comprising:
 a housing structure having a proximal end and a distal end, the housing structure comprising a holding arm arranged at the distal end of the housing structure;   a plunger rod having a proximal end and a distal end, the plunger rod comprising a holding structure arranged at the distal end of the plunger rod, the holding structure being configured to engage with the holding arm in a pre-tensioned state, wherein the plunger rod is operatively arranged to, upon activation, be released from its pre-tensioned state by disengagement of the holding structure from the holding arm of the housing structure, to move proximally inside the housing structure; and   a signal generating member attached to the housing structure, the signal generating member being arranged radially outside of the plunger rod and comprising a resilient tongue which in the pre-tensioned state of the plunger rod is arranged in contact with a first portion of the plunger rod,   wherein the plunger rod comprises a second portion arranged distally from the first portion, the second portion comprising a cut-out, and wherein the resilient tongue is operably arranged to, upon movement of the plunger rod in the proximal direction, be brought into contact with the second portion of the plunger rod to interact with the cut-out for generating an audible and/or tactile feedback.   
     
     
         16 . The feedback mechanism according to  claim 15 , wherein the plunger rod is, upon activation, movable between a first end position and a second end position, and wherein the resilient tongue is arranged in pre-tensioned contact with the first portion of the plunger rod in the first end position of the plunger rod, and is arranged to interact with the cut-out for generating an audible and/or tactile feedback in the second end position of the plunger rod. 
     
     
         17 . The feedback mechanism according to  claim 15 , wherein the first portion of the plunger rod comprises a cut-out which the resilient tongue is in pre-tensioned contact in the pre-tensioned state of the plunger rod. 
     
     
         18 . The feedback mechanism according to  claim 17 , wherein the plunger rod comprises an external surface having an intermediate portion arranged axially between the first portion and the second portion, wherein the intermediate portion is arranged to support and flex the resilient tongue radially outwards upon movement of the plunger rod in the proximal direction. 
     
     
         19 . The feedback mechanism according to  claim 18 , wherein the diameter of the plunger rod at the intermediate portion is larger than the diameter of the plunger rod at the cut out of the second portion. 
     
     
         20 . The feedback mechanism according to  claim 15 , wherein the cut-out of the second portion of the plunger rod is an indentation in the plunger rod. 
     
     
         21 . The feedback mechanism according to  claim 20 , wherein the resilient tongue is arranged to, upon movement of the plunger rod in the proximal direction, be brought into contact with the indentation for generating the audible and/or tactile feedback 
     
     
         22 . The feedback mechanism according to  claim 15 , wherein the cut-out of the second portion of the plunger rod is a through hole in the plunger rod. 
     
     
         23 . The feedback mechanism according to  claim 15 , further comprising a drive spring operably arranged to act on the plunger rod to exert a force in the proximal direction, wherein the plunger rod is arranged radially outwards of the drive spring. 
     
     
         24 . The feedback mechanism according to  claim 22 , wherein the resilient tongue is arranged to, upon movement of the plunger rod in the proximal direction, be brought into contact with the drive spring via the through hole for generating the audible and/or tactile feedback. 
     
     
         25 . The feedback mechanism according to  claim 15 , wherein the signal generating member comprises a sleeve surrounding the plunger rod, wherein the resilient tongue protrudes radially inwards from the sleeve. 
     
     
         26 . The feedback mechanism according to  claim 25 , wherein the resilient tongue is a first resilient tongue, and the signal generating member comprises a second a resilient tongue protruding radially inwards from the sleeve opposite to the first resilient tongue. 
     
     
         27 . The feedback mechanism according to  claim 25 , wherein the signal generator member comprises an attachment arm extending distally from the sleeve, wherein the attachment arm is fixedly attached to the housing structure. 
     
     
         28 . A medicament delivery device comprising a feedback mechanism according to  claim 15 .